Refrigerant Compressor

ABSTRACT

Oil recirculation mechanism includes an oil separation portion (separation chamber  104   b   2 , separation pipe  130 ) for separating oil from a discharged refrigerant, oil storage chamber  132  for storing the separated oil, oil return passage through which the oil storage chamber  132  communicates with the suction chamber  119 , and orifice  136  with a filter. The oil storage chamber  132  extends in a diametric direction of a compressor housing and has an open end at an outer face of the housing, and the open end is occluded by an occluding member. A partition wall (bulge portion  132   a ), that separates the oil storage chamber  132  from the suction chamber  119 , is disposed in a region more inside than the opening of the open end. An oil return passage is linearly formed through the partition wall and the orifice  136  with a filter is accommodated and positioned in the oil return passage.

TECHNICAL FIELD

The present invention relates to a refrigerant compressor to be used for a vehicle air-conditioning systems, and the like, and more specifically, relates to a recirculation structure for lubrication oils.

BACKGROUND ART

In a refrigerant compressor, a lubrication oil is mixed in a refrigerant drawn into and discharged from the refrigerant compressor, but when an oil circulation rate (OCR) to an aft-conditioning system becomes high, heat exchange is prevented and the cooling performance drops. Accordingly, it is required to lower the oil circulation rate.

Therefore, as described in Patent Document 1, an oil recirculation mechanism is provided, which separates an oil from a refrigerant discharged from a compressing mechanism and returns the oil to a suction pressure region of the compressing mechanism.

The oil recirculation mechanism includes an oil-separation portion (separation chamber 41 and separation tube 43) for separating an oil from the refrigerant, an oil storage chamber (oil retaining chamber 44) for storing the separated oil, an oil return passage (oil supply passage 61 a, 61 b) through which the oil storage chamber communicates with a suction pressure region, and an orifice (fluid restrictor 62) that is a depressurizing device provided in the oil return passage.

CITATION LIST Patent Document

-   Patent Document 1: Japanese Laid-Open Patent Application Publication     No. 2000-080983

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Thus, in order to return the oil separated from the discharged refrigerant to the suction pressure region, in addition to the oil storage chamber and the oil return passage, it is necessary to provide an orifice as a depressurizing device in the oil return passage. Furthermore, in order to prevent clogging of such an orifice, it is necessary to provide a filter on the upstream side of the orifice.

Accordingly, it is necessary to add elements, that are an oil storage chamber, an oil return passage and a depressurizing device (orifice), to constitute an oil recirculation mechanism on a cylinder head side of a compressor housing, and further, it is necessary to add a filter. Since it is necessary to lay out these elements in the housing under various design restrictions, a process for forming and fabricating the housing becomes complicated, which has been causing deterioration of productivity.

Under these circumstances, it is an object of the present invention to provide a refrigerant compressor which has an oil recirculation mechanism excellent in productivity.

Means for Solving the Problems

A refrigerant compressor according to the present invention premises a construction including a compressing mechanism that compresses a refrigerant gas drawn from an external refrigerant circuit and discharges the compressed refrigerant, and an oil recirculation mechanism that separates a lubrication oil from the refrigerant discharged from the compressing mechanism and returns the lubrication oil to a suction pressure region of the compressing mechanism.

Here, the oil recirculation mechanism includes: an oil separation portion for separating an oil from the discharged refrigerant; an oil storage chamber for storing the oil separated by the oil separation portion; an oil return passage through which the oil storage chamber communicates with the suction pressure region; and a depressurizing device provided in the oil return passage.

Furthermore, the oil storage chamber extends in a diametric direction of a compressor housing and has an open end at an outer face of the housing, the open end is occluded by an occluding member; a partition wall, that separates the oil storage chamber from the suction pressure region, is present in a region more inside than the opening of the open end; a through-hole, that is the oil return passage and that penetrates through the partition wall and has one end which opens to the oil storage chamber and the other end which opens to the suction pressure region, is linearly formed so that the through-hole can be observed from the opening of the open end; and the depressurizing device is accommodated and positioned in the through-hole.

Effects of the Invention

According to the present invention, since the oil return passage and the depressurizing device are disposed in a region of the oil storage chamber more inside than the opening of the open end, it is possible to accommodate the oil recirculation mechanism compactly. Further, it is possible to easily form the oil return passage (through-hole) from the open end side of the oil storage chamber, and it is possible to easily attach the depressurizing device. Furthermore, since the attachment of the depressurizing device is easy, attachment of a depressurizing device with a filter also becomes easy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a refrigerant compressor (in particular, a variable displacement compressor) illustrating an embodiment of the present invention.

FIG. 2 is an A-A cross-sectional view of FIG. 1

FIG. 3 is a view observed from an arrow B of FIG. 2 (a view of an oil storage chamber observed from its open end side).

FIG. 4 is a C-C cross-sectional view of FIG. 2.

FIG. 5 is an enlarged view of an orifice with a filter.

FIG. 6 is a view of an oil storage chamber illustrating another embodiment of the present invention observed from its open end side.

MODES OF CARRYING OUT THE INVENTION

Now embodiments of the present invention will be described in detail.

FIG. 1 is a cross-sectional view of a refrigerant compressor (in particular, a variable displacement compressor) illustrating an embodiment of the present invention. Further, FIG. 2 is an A-A cross-sectional view of FIG. 1, FIG. 3 is a view observed from an arrow B of FIG. 2, and FIG. 4 is a C-C cross-sectional view of FIG. 2. Here, FIG. 3 is a view of an oil storage chamber 132 observed from its open end side, wherein an occluding member 134 and an orifice 136 are not illustrated. Further, FIG. 5 is an enlarged view of an orifice with a filter.

First, the basic construction of a variable displacement compressor will be described.

A variable displacement compressor 100 includes a cylinder block 101 that has a plurality of cylinder bores 101 a disposed in parallel to and around the axis of the cylinder block 101; a front housing 102 that is provided on one end of the cylinder block 101; and a cylinder head (rear housing) 104 that is provided on the other end of the cylinder block 101 with a valve plate (valve-port-formed member) 103 interposed therebetween. These components as well as interposed gaskets, which are not illustrated, are fastened together by bolts 140 to constitute a compressor housing.

In the central portions of the cylinder block 101 and the front housing 102, a drive shaft 106 is provided so as to extend laterally across a crank chamber 105 formed between the cylinder block 101 and the front housing 102, and a swash plate 107 is disposed around the drive shaft 106. The swash plate 107 is coupled via a connecting unit 109 with a rotor 108 fixed to the drive shaft 106, so that the inclination angle of the swash plate 107 along the drive shaft 106 is variable. Here, between the rotor 108 and the swash plate 107, a coil spring 110 for urging a force to the swash plate 107 toward the minimum inclination angle is attached, and further, on the other side across the swash plate 107, a coil spring 111 for urging a force to the swash plate 107 toward a direction of increasing the inclination angle is attached.

One end of the drive shaft 106 extends through a boss portion 102 a protruding outwardly from the front housing 102, to the outside and is connected to an electromagnetic clutch, which is not illustrated. Here, between the drive shaft 106 and the boss portion 102 a, a shaft seal device 112 is inserted so as to form a sealing between the inside and the outside of the front housing 102. The drive shaft 106 is supported by bearings 113, 114, 115 and 116 in radial and thrust directions, so that a drive force from an external drive source is propagated via the electromagnetic clutch to rotate the shaft 106.

In each cylinder bore 101 a of the cylinder block 101, a single head type piston 117 is inserted and disposed so that its head is on the cylinder head 104 side and that the piston 117 is reciprocatable. On the other end portion of the piston 117 opposite to the piston head, a rectangular recess 117 a is formed, and the outer peripheral portion of the swash plate 107 is accommodated in the recess 117 a so that the piston 117 and the swash plate 107 are configured to interlock with each other via a pair of front and rear shoes 118. Accordingly, by rotation of the drive shaft 106, each piston 117 can be reciprocated in each cylinder bore 101 a.

Inside of the cylinder head 104 is compartmented to form a suction chamber 119 and a discharge chamber 120. The suction chamber 119 is disposed on the center side in the diametric direction of the cylinder head 104 (on the extended axial line of the drive shaft 106), and the discharge chamber 120 is disposed on the outer side in the diametric direction of the cylinder head 104 so as to be in an annular form encircling the suction chamber 119.

In the valve plate 103, suction ports 103 a through which the cylinder bores 101 a (compression chambers of pistons 117) communicate with the suction chamber 119 in the cylinder head 104, and discharge ports 103 b through which the cylinder bores 101 a (compression chambers of pistons 117) communicate with the discharge chamber 120 in the cylinder head 104, are formed. In each suction port and each discharge port, a one-way valve (not illustrated) is provided.

In the cylinder head 104, as illustrated in FIG. 2, a suction passage 104 a for introducing a refrigerant drawn from an external refrigerant circuit into the suction chamber 119, and a discharge passage 104 b for leading out a refrigerant discharged into the discharge chamber 120 to the external refrigerant circuit, are provided. Accordingly, the suction chamber 119 is connected to an air-conditioning system side via the suction passage 104 a and the discharge chamber 120 is connected to the air-conditioning system side via the discharge passage 104 b.

In this variable displacement compressor 100, rotation of the drive shaft 106 is converted by the swash plate 107 being a conversion mechanism into reciprocal movement of each piston 117, to draw and discharge the refrigerant. Here, the displacement can be changed by changing the stroke of each piston 117 by adjusting the inclination angle of the swash plate 107, and the inclination angle of the swash plate 107 is changed by the pressure in the crank chamber 105.

That is, since the inclination angle of the swash plate 107 is changed by a moment caused by pressure differences between front and back sides of all pistons 117, it is possible to optionally control the inclination angle of the swash plate 107 by the pressure in the crank chamber 105.

In order to achieve this control, a displacement control valve 200 is provided in the cylinder head 104. The displacement control valve 200 changes the opening degree of a gas supply passage 121 through which the discharge chamber 120 communicates with the crank chamber 105, to adjust an introduction amount of a discharge gas into the crank chamber 105.

Further, a refrigerant in the crank chamber 105 flows into the suction chamber 119 via a gas-extraction passage that passes through gaps between the drive shaft 106 and the bearings 115 and 116, a space 122 and an orifice 103 c formed in the valve plate 103.

Accordingly, by adjusting the opening degree of the displacement control valve 200, it is possible to change the pressure in the crank chamber 105 to change the inclination angle of the swash plate 107, and thereby to change the displacement. Here, the pressure in the suction chamber 119 is introduced into the displacement control valve 200 via a communication passage 123, and the displacement control valve 200 adjusts the introduction amount of the discharge gas into the crank chamber 105 so that the suction chamber 119 maintains a predetermined pressure.

Next, an oil recirculation mechanism will be described with reference to FIGS. 2 to 4, which separates a lubrication oil from a refrigerant discharged from a compressing mechanism (compressing mechanism that is constituted by a piston 117 and the like, and compresses a refrigerant sucked from an external refrigerant circuit and discharges the compressed refrigerant) and returns the separated lubrication oil to a suction pressure region of the compressing mechanism.

The oil recirculation mechanism includes an oil separation portion for separating an oil from the discharged refrigerant, an oil storage chamber for storing the separated oil, an oil return passage through which the oil storage chamber communicates with a suction pressure region, and a depressurizing device provided in the oil return passage.

The discharge passage 104 b is constituted by a lead-out hole 104 b 1 that is an upward hole provided in an upper region of the cylinder head 104 and connected to an external refrigerant circuit; a separation chamber 104 b 2 that has a cylindrical shape of which diameter is greater than that of the lead-out hole 104 b 1 and disposed substantially coaxially with the lead-out hole 104 b 1 and below the lead-out hole 104 b 1; an separation pipe 130 projecting into the separation chamber 104 b 2 and press-fit into and fixed to the lead-out hole 104 b 1; and an introduction hole 104 b 3 extending in a direction substantially perpendicular to the axial line of the separation chamber 104 b 2 and opening along an inner wall of the separation chamber 104 b 2, through which the separation chamber 104 b 2 communicates with the discharge chamber 120.

Accordingly, a gas-state refrigerant, that is discharged from each cylinder bore 101 a into the discharge chamber 120 and contains an oil, flows through the introduction hole 104 b 3 into the separation chamber 104 b 2, and while the refrigerant whirls around the separation pipe 130, an oil is separated and a gas-state refrigerant is discharged through the inside of the separation pipe 130 and the lead-out hole 104 b 1 into the external refrigerant circuit. The introduction hole 104 b 3, the separation chamber 104 b 2 and the separation pipe 130 constitute an oil separation portion for separating an oil from the discharged refrigerant.

In order to store the oil separated by the oil separation portion, an oil storage chamber 132 is provided.

The oil storage chamber 132 extends in the diametric direction of the cylinder head 104 and has an open end which opens downwardly at the outer face of the cylinder head 104, the oil storage chamber 132 is formed so that its opening area increases toward the open end, and the oil storage chamber 132 at the open end side has a cylindrical shape. The open end is occluded by the occluding member 134. The oil storage chamber 132 has a region bulging into the suction chamber 119 and the discharge chamber 120 so as to suppress increase of size of the compressor.

An open end of the separation chamber 104 b 2 opens directly into a region of the oil storage chamber 132 opposing to the occluding member 134, and an oil separated in the separation chamber 104 b 2 drops directly into the oil storage chamber 132 and is stored. That is, the open end of the separation chamber 104 b 2 acts as a role of an oil introduction hole into the oil storage chamber 132.

In the oil storage chamber 132, a bulge portion 132 a is provided so as to bulge into a region more inside than the opening of the open end, and the bulge portion 132 a forms a partition wall separating the oil storage chamber 132 from the suction chamber 119. Further, through the bulge portion 132 a forming the partition, a through-hole 132 b being an oil return passage having one end which opens into the oil storage chamber 132 and the other end which opens into the suction chamber 119, is formed linearly so that the through-hole can be observed from the opening of the open end.

In the through-hole 132 b, an orifice (orifice with a filter) functioning as a depressurizing device is accommodated and fixed. FIG. 5 is an enlarged view illustrating the orifice with a filter.

The orifice 136 includes an orifice member 136 a having a pipe shape and limiting a flow rate by its inner diameter, and a filter 136 b made of a resin and covering an oil chamber side opening of the orifice member 136 a. The filter 136 b is constituted by a frame 136 b 1 having a tubular shape and a filter member 136 b 2 attached to the inner face of the frame 136 b 1. The filter 136 b is disposed so as to protrude into the oil storage chamber 132 so that the tip of the filter 136 b 1 faces in proximity to the tip of the occluding member 134. That is, the occluding member 134 also functions of preventing the orifice 136 from coming out from the through-hole 132 b.

Further, between the inner periphery of the through-hole 132 b and the outer periphery of the orifice 136, an o-ring 138 being a sealing member is provided, and the orifice 136 is retained in the through-hole 132 b by elasticity of the o-ring 138.

Here, the diameter of the orifice 136, that is the inner diameter of the pipe-shaped orifice member 136 a, is set so that an oil is stored in the oil storage chamber 132.

Accordingly, an oil separated in the separation chamber 104 b 2 is stored in the oil storage chamber 132, and an oil stored in the oil storage chamber 132 is returned to the suction chamber 119 through the orifice 136 (orifice member 136 a) by a pressure difference between the oil storage chamber 132 and the suction chamber 119.

The above oil recirculation mechanism provides the following effects.

Since the oil return passage (through-hole 132 b) is linearly provided in a region of the oil storage chamber 132 more inside than the open end and the orifice with a filter is provided in the oil return passage (through-hole 132 b), it is possible to accommodate the oil recirculation mechanism compactly.

Further, it is possible to easily form the oil return passage (through-hole 136 b) and the oil introduction hole (separation chamber 104 b 2) from the open end side of the oil storage chamber 132, and it is possible to easily attach the orifice 136. Accordingly, such a construction is excellent in productivity.

Furthermore, the oil storage chamber 132 extends in the diametric direction of the cylinder head 104 and has an open end which opens downwardly at the outer face of the cylinder head 104, and the oil storage chamber 132 is formed so that its opening area increases toward the open end, the volume increases toward a lower region (occluding member 134 side) of the oil storage chamber 132. Thus, it is possible to obtain an oil-storing space effectively and to form the oil storage chamber 132 easily by casting.

Furthermore, in a cylinder head 104 in which the suction chamber 119 is disposed on an extended line of the axis of a drive shaft 106 and the discharge chamber 120 is disposed in an annular form so as to encircle the suction chamber 119 in the diametric direction, it is possible to easily dispose an oil introduction hole into the oil storage chamber 132 in an upper region of the cylinder head 104, and accordingly, it is possible to obtain a space for the oil storage chamber 132 in a lower region of the cylinder head 104 without significantly increasing the size of the compressor.

Furthermore, according to the embodiment of the present invention, between the inner periphery of the through-hole 132 b and the outer periphery of the depressurizing device (orifice 136), a sealing member (o-ring 138) is provided, the depressurizing device (orifice 136) has a filter 136 b covering an oil storage chamber side opening of the depressurizing device, and the filter 136 b protrudes into the oil storage chamber so that the tip of the filter 136 b faces in proximity to the tip of the occluding member 134. Accordingly, the occluding member 134 functions of preventing the filter 136 b and the orifice 136 from coming out from the through-hole 132 b, and it is not necessary to fix the depressurizing device (orifice 136) to the housing and thus attachment becomes easy. Further, since the depressurizing device (orifice 136) can be removed easily by removing the occluding member 134, such a construction is excellent in maintainability.

Furthermore, according to the embodiment of the present invention, the oil storage chamber 132 extends in the vertical direction so that the open end is on the lower side, and the oil introduction hole (open end of the separation chamber 104 b 2) into the oil storage chamber 132 is formed in a region opposing to the opening of the open end, and thus, it is possible to easily form the oil introduction hole from the open end side of the oil storage chamber 132.

Furthermore, according to the embodiment of the present invention, since the oil storage chamber 132 is formed so that its opening area increases toward the open end, the volume increases toward a lower region (occluding member 134 side) of the oil storage chamber 132 and it is possible to obtain an oil-storing space effectively and to form the oil storage chamber easily by casting.

Here, the embodiments illustrated in the drawings are only examples of the present invention, and it is a matter of course that the present invention includes not only the constructions directly illustrated in the above embodiments, but also various improvements and modifications within the scope of claims usually done by a person skilled in the art.

For example, the oil separation portion is of a centrifugal separation type employing a separation pipe 130 in the above embodiments, but the separation pipe 130 is not necessarily employed. Further, the oil separation portion may be of another separation type such as a collision separation type, or a region in the discharge chamber 120 in which an oil tends to be accumulated may communicate with the oil separation chamber 132.

Furthermore, in the above embodiment, the oil storage chamber 132 extends in the vertical direction so that the open end is on the lower side, but the construction is not necessarily limited thereto, and the oil storage chamber 132 may be disposed so as to be inclined so that the open end is on the lower side.

Furthermore, in the above embodiment, a bulge portion is provided in the oil storage chamber and a through-hole is formed linearly through the bulge portion, but as illustrated in FIG. 6, the bulge portion is not necessarily provided. FIG. 6 illustrates an oil storage chamber constituted by two cylindrical portions including a large diameter portion 132 c and a small diameter portion 132 d, in which the axis of the large diameter portion 132 c is off the axis of the small diameter portion 132 d so as to form a through-hole 132 b (a partition wall separating the oil storage chamber from the suction chamber and a through-hole 132 b formed therethrough) in a region inside the opening of the open end.

In such a configuration, it is not necessary to form the oil storage chamber into a complex shape and it is possible to easily form the oil storage chamber.

Furthermore, in the above embodiment, a fixed orifice is employed as the depressurizing device, and, as the depressurizing device, a variable orifice or a valve of which opening degree is variable may be employed.

Furthermore, in the above embodiment, the suction chamber 119 is disposed on an extended line of the axis of a drive shaft 106 and the discharge chamber 120 is disposed in an annular form so as to encircle the suction chamber 119 in the diametric direction. In contrast to the abovementioned arrangement, the arrangement in which the discharge chamber 120 is disposed on an extended line of the axis of a drive shaft 106 and the suction chamber 119 is disposed in an annular form so as to encircle the discharge chamber 120 in the diametric direction, may be employed.

Furthermore, in the above embodiment, a reciprocation type variable displacement compressor is employed as the refrigerant compressor, and the refrigerant compressor may be a fixed displacement compressor. Furthermore, the compressor may be employs another compressing mechanism such as a scroll compressor or a vane compressor.

REFERENCE SYMBOLS

-   100 variable displacement compressor -   101 cylinder block -   101 a cylinder bore -   102 front housing -   102 a boss portion -   103 valve plate -   103 a suction port -   103 b discharge port -   103 c orifice -   104 cylinder head (rear housing) -   104 a suction passage -   104 b discharge passage -   104 b 1 lead-out hole -   104 b 2 separation chamber -   104 b 3 introduction hole -   105 crank chamber -   106 drive shaft -   107 swash plate -   108 rotor -   109 connecting unit -   110, 111 coil spring -   112 shaft seal device -   113, 114, 115, 116 bearing -   117 piston -   117 a recess -   118 shoe -   119 suction chamber -   120 discharge chamber -   121 gas supply passage -   122 space -   123 communication passage -   130 separation pipe -   132 oil storage chamber -   132 a bulge portion (partition wall) -   132 b through-hole (oil return passage) -   134 occluding member -   136 orifice (depressurizing device) -   136 a orifice member -   136 b filter -   136 b 1 frame -   136 b 2 filter member -   138 o-ring -   140 fastening bolt -   200 displacement control valve 

1. A refrigerant compressor which includes: a compressing mechanism that compresses a refrigerant drawn from an external refrigerant circuit and discharges the compressed refrigerant; and an oil recirculation mechanism that separates a lubrication oil from the refrigerant discharged from the compressing mechanism and returns the lubrication oil to a suction pressure region of the compressing mechanism, the oil recirculation mechanism comprising: an oil separation portion for separating an oil from the discharged refrigerant; an oil storage chamber for storing the oil separated by the oil separation portion; an oil return passage through which the oil storage chamber communicates with the suction pressure region; and a depressurizing device provided in the oil return passage, wherein the oil storage chamber extends in a diametric direction of a compressor housing and has an open end at an outer face of the housing, and the open end is occluded by an occluding member; wherein a partition wall, that separates the oil storage chamber from the suction pressure region, is disposed in a region more inside than the opening of the open end; wherein a through-hole, that is the oil return passage and that penetrates through the partition wall and has one end opening to the oil storage chamber and the other end opening to the suction pressure region, is linearly formed so that the through-hole is observed from the opening of the open end; and wherein the depressurizing device is accommodated and positioned in the through-hole.
 2. The refrigerant compressor according to claim 1, wherein a sealing member is provided between an inner periphery of the through-hole and an outer periphery of the depressurizing device, wherein the depressurizing device has a filter covering an oil storage chamber side entrance portion of the pressurizing device, and wherein the filter protrudes into the oil storage chamber so that the tip of the filter faces in proximity to the occluding member.
 3. The refrigerant compressor according to claim 1, wherein the oil storage chamber extends in the vertical direction so that the open end is on the lower side, and an oil introduction hole to the oil storage chamber is formed in a region opposing to the opening of the open end.
 4. The refrigerant compressor according to claim 1, wherein the oil storage chamber is formed so that its opening area increases toward the open end. 